ARM: dts: rockchip: add rk3288 arm-pmu irq affinity

The rk3288 uses spi irqs for the arm-pmu on individual cpu cores, so needs
the affinity to them defined.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Sonny Rao <sonnyrao@chromium.org>